Production Log Interpretation Through A Slotted Liner During Cold - PowerPoint PPT Presentation

Production Log Interpretation Through A Slotted Liner During Cold Water Injection: Integration With Electrical Borehole Images In A High Temperature Geothermal Development Well, South Sumatra, Indonesia Richard E. Netherwood, Dibyatanu Kundu, Aditi Pal, Mega Ardhiani Puspa PT Schlumberger Geophysics Nusantara, Jakarta, Indonesia M. Yustin Kamah, Dratjat Budi Hartanto, M. Husni Thamrin PT Pertamina Geothermal Energy, Jakarta, Indonesia 2 nd Africal Rift Geothermal Conference 1 REN/KUNDU 6/3/2009 November 2008

Outlin e � Introduction – Indonesia’s geothermal resources – Wireline log acquisition in geothermal wells – Electrical borehole images and production logs � Interpretation – Fractures, faults, drilling induced features – Integrated fracture and production log analysis � Conclusions 2 nd Africal Rift Geothermal Conference 2 REN/KUNDU 6/3/2009 November 2008

Indonesia, Geothermal Resources (Map from Fauzi et al. 2000; capacities from Fauzi et al. 2005) Sumatera Sibayak 10 Sulawesi MW Lahendong 40 Sarulla 220 MW MW Java Kamojang 200 MW Darajat 255 MW 121 active volcanoes Gn.Salak 330 MW … and up to 27,000 MW potential Wayang-Windu 220 MW Dieng 180 MW 2 nd Africal Rift Geothermal Conference 3 REN/KUNDU 6/3/2009 November 2008

Wireline Log Acquisition In Geothermal Wells � Issues – Temperatures recorded at >350 o C • Tools commonly rated only to 250 o C, often <250 o C – Steam in wellbore • The physics of most tools depend on water filling the wellbore � Solutions – Special Hi Temp tools • Few, very expensive and generally inferior – Cooling flasks for some tools • Limited tools, and not for image and production logs – Cooling the borehole with water • Also provides the correct borehole medium for logging • Uses untreated river water • Only in >/= 8.5” borehole. 6” borehole produces “rocket” effect and cable pull-off • The suite: electrical borehole imaging tool – in open hole • Production logging tool – inside slotted liner 2 nd Africal Rift Geothermal Conference 4 REN/KUNDU 6/3/2009 November 2008

Electrical Borehole Imaging Tool � Alternating current is emitted from an upper electrode � Passive focusing: lower electrodes form an equi- potential surface parallel to borehole wall � Detected current is P / T 20,000psi / 350 oF determined by the Tool diameter 5” formation resistivity Maximum Aperture 21” � Constant feedback Image resolution 0.2” (0.5 cm)c.1” Borehole coverage 80% in 8” optimizes input hole current for formation Combinability Bottom of string characteristics 2 nd Africal Rift Geothermal Conference 5 REN/KUNDU 6/3/2009 November 2008

Electrical Borehole Image Processing (1) 24 buttons x 8 pads = 192 resistivity curves (fast channels: colour-scaled to generate image) Dark = conductive Light = resistive 2 nd Africal Rift Geothermal Conference 6 REN/KUNDU 6/3/2009 November 2008

Electrical Borehole Image Processing (2) STATIC DYNAMIC Static – – resistivity resistivity distribution over the entire logging run distribution over the entire logging run Static Frequency Frequency Dynamic Dynamic – – resistivity resistivity distrib distrib. 2ft / 1m intervals with overlap . 2ft / 1m intervals with overlap CONDUCTIVE RESISTIVE 2 nd Africal Rift Geothermal Conference 7 REN/KUNDU 6/3/2009 November 2008

Electrical Borehole Image Processing (3) S E S N E S W N W E N W N E S W N N Am Az 0 ° 90 ° 180 ° 270 ° 360 ° E S Images Viewed Inside Out N W Planar features crossing the borehole describe a sinewave on the image Am=dip magnitude, Az=azimuth Natural fractures: represented by dip azimuth, strike and magnitude 2 nd Africal Rift Geothermal Conference 8 REN/KUNDU 6/3/2009 November 2008

Production Logging Tool 2 nd Africal Rift Geothermal Conference 9 REN/KUNDU 6/3/2009 November 2008

Production Logging Tool Processing 2 nd Africal Rift Geothermal Conference 10 REN/KUNDU 6/3/2009 November 2008

INTERPRETATION 2 nd Africal Rift Geothermal Conference 11 REN/KUNDU 6/3/2009 November 2008

Fracture & Fault Classification Conductive (open) Resistive (healed) Fault (minor) Drilling induced fractures fractures fractures 2 nd Africal Rift Geothermal Conference 12 REN/KUNDU 6/3/2009 November 2008

Fracture Distribution 2 nd Africal Rift Geothermal Conference 13 REN/KUNDU 6/3/2009 November 2008

Fracture & Fault Orientation Conductiv Resistive Fault e (healed) s (open) fractures fractures Drilling Induced SHma fractures x Faults and fractures all strike NNW-SSE parallel to SHmax Shmin 2 nd Africal Rift Geothermal Conference 14 REN/KUNDU 6/3/2009 November 2008

UPPER INTERVAL: 880-1869m Open hole: 12.25” Slotted liner: 9.625” 2 nd Africal Rift Geothermal Conference 15 REN/KUNDU 6/3/2009 November 2008

1. 1,100 m – 8,897 bbl/d flow into wellbore In: 23,173 bbl/d Major increase in flow rate according to spinner reading. Corresponding temperature increase and fluid density decrease. Flow into the borehole from Out: 8,900 the formation is 8,897 bbl/d. bbl/d Fault observed on image. POTENTIAL MAJOR PRODUCTION ZONE 2 nd Africal Rift Geothermal Conference 16 REN/KUNDU 6/3/2009 November 2008

2. 1,180 m – local anomally, no net flow loss/gain In: 23,173 bbl/d Minor/local increase in flow rate according to spinner readings, but no overall increase in flow. No temperature increase or No image. fluid density decrease. Major Washout washout and change in Out: 8,900 formation lithology. Flow disturbance associated bbl/d with major washout. NO PRODUCTION POTENTIAL 2 nd Africal Rift Geothermal Conference 17 REN/KUNDU 6/3/2009 November 2008

3. 1,180-1,550 m – 2,065 bbl/d flow into formation In: 23,173 bbl/d Out: 8,900 Minor 2,065 bbl/d flow into the formation. Absence bbl/d of any major conductive open fractures. Dominance of resistive healed fractures. NEGLIGIBLE PRODUCTION POTENTIAL 2 nd Africal Rift Geothermal Conference 18 REN/KUNDU 6/3/2009 November 2008

4. 1,550-1,780 m – 21,147 bbl/d flow into formation In: 23,173 bbl/d Out: 8,900 Major flow of 21,147 bbp/d into the formation associated with abundant open fractures, bbl/d particularly over intervals 1,546-1,554m and 1,660-1,780m. POTENTIAL MAJOR PRODUCTION ZONE 2 nd Africal Rift Geothermal Conference 19 REN/KUNDU 6/3/2009 November 2008

LOWER INTERVAL: 1880-2271m Open hole: 8.5” Slotted liner: 7” 2 nd Africal Rift Geothermal Conference 20 REN/KUNDU 6/3/2009 November 2008

5. 1,830-1,860 m – 770 bbl/d flow into wellbore In: 8.900 bbl/d 5 6 Minor flow of 770 bbp/d into the wellbore. Associated with faults at 1,831 m and 1.861 m, and Out: 2,650 7 associated conductive fractures. bbl/d POTENTIAL MINOR 8 PRODUCTION ZONE 2 nd Africal Rift Geothermal Conference 21 REN/KUNDU 6/3/2009 November 2008

6. 1,860-1,930 m – 4,763 bbl/d flow into formation In: 8.900 bbl/d 5 6 Significant flow of 4,763 bbp/d Out: 2,650 7 into the formation. Associated bbl/d with fault at 1,917m with 8 associated washout. POTENTIAL MINOR 2 nd Africal Rift Geothermal Conference 22 REN/KUNDU PRODUCTION 6/3/2009 November 2008

7. 2,170-2,260 m – 2,334 bbl/d flow into formation In: 8.900 bbl/d 5 6 Significant flow of 2,334 bbp/d Out: 2,650 7 into the formation. Associated bbl/d with open fractures and local 8 faults. POTENTIAL MINOR 2 nd Africal Rift Geothermal Conference 23 REN/KUNDU PRODUCTION 6/3/2009 November 2008

8. Below 2,271 m – 2,650 bbl/d flow into formation In: 8.900 bbl/d 2,650 bbl/d flow is calculated below 5 the last logged depth (TD). It is possible that this represents calculation error, but the lack of a 6 standing water column at the base of the well supports continued downward flow (into fractures?). Out: 2,650 7 POTENTIAL MINOR bbl/d PRODUCTION 8 2 nd Africal Rift Geothermal Conference 24 REN/KUNDU 6/3/2009 November 2008

Conclusions � Injection of cold water into geothermal wells allows acquisition of standard P&T rated logging tool data � Electrical borehole images provide an excellent way to identify, classify, quantify & orientate fractures, faults, and borehole damage, the latter indicating stress direction � Electrical borehole images alone do not, however, identify which fractures will or will not produce � Integration of image data with production logging data can identify individual fractures, fracture zones and faults that will potentially produce steam 2 nd Africal Rift Geothermal Conference 25 REN/KUNDU 6/3/2009 November 2008